Field of the Invention
This invention relates generally to automotive occupant safety systems such as airbag installations for automotive vehicles and, more particularly, to mounting systems and components of such systems and the manufacture thereof.
Discussion of Related Art
It is well known to protect a vehicle occupant by means of safety restraint systems which self-actuate from an undeployed or static state to a deployed state without the need for intervention by the operator, i.e., “passive restraint systems.” Such systems commonly contain or include an inflatable vehicle occupant restraint or element, such as in the form of a cushion or bag, commonly referred to as an “airbag cushion.” In practice, such airbag cushions are typically designed to rapidly inflate or expand with gas when the vehicle encounters a sudden deceleration, such as in the event of a collision.
Such airbag cushions may desirably deploy into one or more locations within the vehicle between the occupant and certain parts of the vehicle interior, such as the doors, steering wheel, instrument panel or the like, to prevent or avoid the occupant from forcibly striking such parts of the vehicle interior. For example, typical or customary vehicular airbag cushion installation locations have included in the steering wheel, in the dashboard on the passenger side of a car, along the roof line of a vehicle such as above a vehicle door, and in the vehicle seat such as in the case of a seat-mounted airbag cushion. Other airbag cushions such as in the form of knee bolsters and overhead airbags can also operate or serve to protect other specific or particular various parts of an occupant's body from collision. In the case of a front airbag, for example, the cushion portion is accommodated in the center of a steering wheel in a folded state. In the case of a curtain airbag, for example, the cushion portion is typically accommodated in the vicinity of an upper portion of a side door in a rolled state in a roll form.
The cushion portion in an accommodated state is preferably maintained in a desired folded or rolled state. For example, in the case of a front airbag cushion installation, since the cushion portion is accommodated in a housing that also functions as a horn switch, the accommodated form is maintained. On the other hand, in the case of a curtain airbag cushion, since the cushion portion has an elongated shape, the cushion portion may typically not have a dedicated housing capable of accommodating the entire cushion portion and the accommodated form thereof is maintained using a tape or the like device or feature.
For example, WO 2014/061452 A1 and its European counterpart, European Patent Application Publication EP 2 910 432 A1, disclose an airbag that includes a cushion portion that is accommodated in a long and narrow form at least in part through the use a device termed a “mounting bracket,” or, more specifically a “hanger bracket” or, more simply, a “hanger” or “bracket.”
FIGS. 1 and 2 illustrate a curtain airbag assembly 100 such as including a cushion portion 102.
The cushion portion 102 is a portion that is inflated and deployed in an emergency situation to protect an occupant. The cushion portion 102 is rolled and accommodated in a narrow and long form in a front-rear direction of a vehicle and is mounted such as by being attached to a wall (e.g., a roof side rail) above a side surface of a vehicle interior. In general, since the roof side rail is commonly covered by a roof trim, the accommodated cushion portion 102 is not visible from the vehicle interior. Although the accommodated form of the cushion portion 102 of this particular illustrated embodiment is realized by winding, the accommodated form may be alternatively be realized by folding or the like, for example.
Typically, a plurality of hanger brackets 112 are provided in an upper portion of the airbag assembly so as to attach the cushion portion 102 to the vehicle. The bracket 112 is typically a metal member and is fixed to the roof side rail after being connected to or with the cushion portion 102.
A wrapping member 114 has a root portion 115 which is sewn or otherwise connected to a fabric tab connector 132 on an upper edge of the cushion portion 102. Hooking holes 116a and 116b are formed in both ends in a width direction of a distal end of the wrapping member 114. After the wrapping member 114 is wrapped, when the hooking holes 116a and 116b are hooked on protruding portions 118a and 118b of the bracket 112, respectively, the cushion portion 102 in the accommodated form is connected to the bracket 112 as illustrated in FIG. 1.
The bracket 112 is commonly formed by applying bending processing or the like to a planar metal. A bolt hole 120 is formed in the bracket 112, and a bolt (not illustrated) passes through the bolt hole 120 whereby the bracket 112 is appropriately fastened to the vehicle, such as to the roof side rail (not shown).
The bracket 112 includes a base portion 122 provided in a lower part of the bracket 112 and has a horizontally long insertion hole 124. The fabric tab 132 passes through the insertion hole 124 and is typically sewn to itself near the bracket 112 and then ultimately sewn or otherwise appropriately connected to or with the cushion. Both ends 124a and 124b in the longitudinal direction of the insertion hole 124 have an upwardly curved shape whereby the concentration of stress when a load is applied from the wrapping member 114, for example, can be alleviated and the occurrence of cracks or the like avoided or prevented.
A vehicle fixing portion 126 extends upward from the base portion 122 in a rectangular shape. The above-described bolt hole 120 and hooking portions 128a and 128b are formed in the vehicle fixing portion 126, and the hooking portions 128a and 128b are formed in lateral edges in the width direction so as to face the vehicle side. The hooking portions 128a and 128b are positioning portions used when attaching the bracket 112 and can desirably be inserted, such as in the vehicle roof side rail, before the bolt is fastened into the bolt hole 120.
The protruding portions 118a and 118b are formed on both sides in the width direction of the vehicle fixing portion 126 in an upper portion of the base portion 122. The protruding portions 118a and 118b have such a shape that protrudes upward from the base portion 122, and the hooking holes 116a and 116b of the wrapping member 114 are hooked on the protruding portions 118a and 118b. 
In this embodiment, as illustrated in FIG. 1, the wrapping member 114 is wrapped around the cushion portion 102 and the bracket 112 in order to maintain the accommodated form of the cushion portion 102 and to connect the cushion portion 102 and the bracket 112. The wrapping member 114 is formed of a breakable material so that the wrapping member 114 breaks with inflation and deployment of the cushion portion 102 so as to open the cushion portion 102. A broken line-shaped slit 130 may be formed in the wrapping member 114 as a weak portion so that breaking occurs smoothly.
As identified above, the root portion 115 of the wrapping member 114 can be sewn or otherwise connected to the fabric tab 132 on the upper edge of the cushion portion 102. Projecting pieces 134a and 134b are formed on a distal end side of the wrapping member 114 on both ends in the width direction, and the hooking holes 116a and 116b are formed in the projecting pieces 134a and 134b, respectively.
Known hanger brackets are typically employed or used with fabric material thicknesses of 1-3 mm or larger for strength as well as to increase the load bearing surface to help prevent or avoid fabric tab tearing during loading. Hanger brackets employed for fabric tab attachment such as used to secure an inflatable curtain airbag to a vehicle and which brackets have a smaller cross sectional area have typically required coining, cold forming, de-burring, and/or coating, to remove or avoid sharp edges that could potentially damage fabric tabs during deployment or throughout their life cycle prior to deployment.
Due to the increased loading on mounting and mounting/hanger brackets due to highly pressurized curtain airbag designs to satisfy evolving regulations, prior art bracket designs may be prone to or can more likely result in tearing of the fabric mounting tabs of the associated airbag cushion. That is, increased frequency and severity of tearing may occur or be experienced due to the increased loading and interaction between the tab and edge of the bracket (which edge is typically less than 3 mm thick).